Long-chain alktl ammonium metallo-



Pa tented Feb. 24,

, MANUFACTURE [av- I LONG-0min AILKYL AMMONIUM ME m'mrms AND raocnss'rALLo. FOR 'rnam {J Y Ma; 'r. Goebel andIsaacF; Walker, Wilmington,

Del., asslgnors to E. I. du Pont de Nemolu-nb Company, Wilmington, Del.,a corporation of Delaware No Drawing.

This invention relates to complex coordination compounds, and moreparticularly to substituted ammonium metallonitrites derived from long--chain aliphatic amines.-

It is well known that certain metal ions are able to' form coordinationcorfiplexes in which .,amine, ethy1amine, aniline, toluidine, monoanddibenzylamine and guanidine: These compounds are-in generalcharacterized by water solubility and in the case of those derivedfromthe lower alkyla-min'es by. instability in the presence of moisture.l r

It is an object of this invention to prepare certain 'new and usefulcompounds.

object is to prepare compounds that are stable in the presence ofmoisture. Still another object is to prepare oil-soluble,water-insoluble comfaces. .Another object is to prepare new, and

pounds having a high aflinity for metallic suruseful compounds havingrust-proofing properties. Another object is to prepare new and usefulcompositions thatfhave rust-proofing qualities. A further object is todevelop a process for the treatment of ferrous metal surfaces to protectthem from corrosion. Other objects will be apparent from the reading ofthe following descrip- I tion of the invention.

These objects are! accomplishedby reacting a compound having a complexmetallonitrite anion with an aliphatic amine having at least one acyclicaliphatic radical 'of at least 8 carbon atoms, and recovering thecoordination product Another Application May 13, 1939; Serial No.273,581

8 Claims. (01.

example Basement-r and CaNi(NOz)e- The substituted ammonium cation isone of the following type where R1 is an acyclic hydrocarbon radicalhaving a chain of at least 8 carbon atoms and where R2, R3, and R4 areeither aliphatic or aromatic.

radicals, it being preferable that-they be hydrocarbon radicals.Compounds coming within the foregoing classification are stable andwaterinsoluble. They are especially adapted for use in coating ferrousmetal surfaces as they form a coating which is of great ;value inretarding rusting or corrosion of said surfaces.

The following examples in which parts are by weight set forth certainwell defined instances of the'application of this invention. They are,

however, not to be considered as limitations.

thereof sincemany modifications may be made without departing from thespirit and scope of thisinvention.

Example I hydrogenation of sperm oil, and 5 parts of glacial formed.This coordination compound contains a complex metallonitrite anion and asubstituted ammonium cation. The metallonitrite anion may contain morethan one kind of metal ion, for

acetic acid in a mixture of parts of 1:1 toluene-acetone and 25 parts ofwater. This mixture is agitated, an additional 50 parts of thetolueneacetone mixture is added, and the water layer is drawn ofl. anddiscarded. The toluene-acetone solution is then evaporated to dryness ona'steam bath and the product obtained is purified by recrystallizationfrom methanol. The mixed alkyl substituted ammonium cobaltinitritesprepared in this manner are lighirorange in color, are soluble in avariety of organic solvents, and

are stable in the presence of moisture. They have the general formula(RNH3)3C0(NO2)6, where It may correspond to the alkyl group inthealcohols obtained by the catalytic hydrogenation of sperm 011. Thesealcohols are chiefly octadecyl alcohol.

E :rample II Fifty parts of hydrated cobaltous acetate and 100 parts oi.sodium nitrite are dissolved in 100 parts of water, and glacial aceticacid is added with stirringuntil no more gas is evolved. The solution iscolored a deep red-brown at this point.

One hundred five parts of n-dodecylamine is then added to the abovesolution, and an immediate reaction occurs, a thick paste being formedand a small amount of N02 being evolved. The paste is dilutedimmediately with cold water and the product separated by filtration. Theorangecolored dodecyl ammonium cobaltinitrite wanamnnoomom,

obtained in this way is Washed several times with cold water and driedin the air at room temperature. This product is similar to that ofExample I in solubility and stability characteristics.

Example III Seventy-six parts of lead acetate and '70 parts of potassiumnitrite-are added to 500 parts of water and the precipitate whichappears is redissolved with a small amount of acetic acid. Sixty partsof crude amines obtainable by reacting ammonia with the mixture ofmonohydric alcohols obtained from the catalytic hydrogenation of coconutoil is added to this solution, and the complex salt is then precipitatedby the addition of potassium hydroxide. When the solid material isfiltered off, a quantity of the amines is recovered in the filtrate, theproportions indicating that the dipotassium salt having the formula isthe product obtained. The presence of a metallic cation in this compoundreduces its oil solubility, but it can be dispersed'successfully invarious organic media and is stable in contact with water.

While cobalt forms particularly stable nitrite complexes, analogouscompounds can be formed with a number of tervalent metals such as iron,nickel, bismuth, ruthenium, rhodium, and iridium. Many bivalent metalsalso producevcompounds of this type, as,for example, copper, lead,mercury, cadmium, zinc, platinum, and palladium. All of these can beused to prepare the products of this invention, but for practicalpurposes it is preferred to use the common metals yielding complexnitrites which, as the alkali metal salts, are soluble in water and canbe heated at moderate temperature without decomposition. Such a groupcomprises cobalt, nickel, lead, cadmium, and mercury, iron, copper, andzinc.

As indicated in the examples, the complex metallonitrites of thisinvention may either contain long-chain alkyl ammonium groups ascations, or there may be present both substituted ammonium radicals ofthis type and metallic ions such as sodium, potassium, barium, calciumand the heavy metals.

The substituted ammonium group is preferably derived from an aliphaticmonoamine having at least one chain of at least eight carbon atoms, butmay also contain aromatic groups as long as the primary requirement ofone aliphatic chain' of at least eight carbons is fulfilled. That is,the primary amines which can be used must be longchain productscontaining at least eight carbon atoms, while the secondary, tertiaryand quaternary ammonium compounds, which also may be used, may containeither aliphatic or aromatic carbon groups as long as one aliphaticchain of at least eight carbon atoms is present. The invention thereforeincludes such compounds as the dodecylammonium,9,10-octadecenylammonium, ditetradecylammonium, tridecylammoninm,hexadecyldimethylam'monium, octadecyldibenzylammonium,hexadecylpyridinium and decamethylenediammonium salts. The longchainalkylammonium group may be derived from either a pure monoor diamine ora technical mixture such as Lorol amine or Stenol amine, whichcorrespond respectively to the alkyl alcohols obtained by the catalytichydrogenation of coconut oil acids and sperm oil. The amines containingfrom 8 to 24 carbon atom chains are ordinarily used because ofavailability and cost considerations, while those containing chains of10 to 18 carbon atoms yield products which are particularly well suitedfor .most applications where these compounds are employed,

Examples of compounds falling within the scope of this invention are asfollows:

Octylphenylammonium copper strontium-nitrite Dodecylpyridinium mercurictrinitrite Pentadecylammonium bismuth nitrite Dioctadecylammonium ironlead nitrite The products of this invention are particularly useful forpreventing corrosion of metal surfaces and may be applied directly toferrous metal surfaces as anti-corrodents or may be incorporated inmetal-protective coating compositions such as drying oil paints,lubricating oils, and lubricants.

Although these compounds will usually be applied to metal surfaces bymeans of a solution using such well known processes as dipping,spraying, wiping, and brushing, it will be desirable at times to useother methods of application. A material which melts at reasonably lowtemperatures and which undergoes no decomposition in the region of itsmelting point may be applied in the liquid form without'a diluent of anykind, provided that the application of the material is so regulated thatthe final protective film conforms to the desired thickness limits.

These compounds may also be applied to the metal surface as e finelydivided solid and the protective layer be formed by fusing the solidparticles to a continuous coating at a suitable temperature. Theprotective agent may also be emulsified or dispersed in a liquid whichis not a true solvent and applied to metal surfaces in this form, withthe evaporation of the carrier occurring subsequently. In some instancesit has been found that oils of various types may serve as carriers forthe protective agent, and in such cases it is not intended that thecarrier be removed by evaporation as is the practice when solventsordispersions are used.

, When applied from solution, concentrations of from 2 to 10% arepreferred although solutions containing 1 to of these compounds may beused. Solvents which are preferred vary with the compounds but ingeneral alcohols, ketones. and hydrocarbons, or'mixtures thereof, arethe most useful.

and such products are particularly valuable as gun oils and lubricantsfor line machinery.

The compounds of this invention are particularly well adapted to theprotection of ferrous metal articles, such as bolts, nuts, nails, wire,sheets, tools, tine machinery parts, bearings, cutlery, gears, flrearms, metallic cases, etc., and

to the treatment of ferrous metal articles which have been provided witha surface coating of some other metal or alloy, such as chromium,

copper, nickel, cadmium, zinc, brass, aluminum, I

tin, lead, etc. In addition to such uses, these compounds may be appliedto the surfaces of other metals and alloys, particularly those used forstructural shapes and articles of commerce such as rods, sheets, tubes,etc. Among such metals are zinc, brass, bronze, aluminum, tin,

The rust-inhibitive power of nitrites isknown,

since soluble inorganic nitrites are often used in solution to protectwater pipes and boilers in power plants and heating systems. Insolublenitrites, such as potassium cobaltinitrite, have also been used asmetal-protective pigments but with only lndiiferent success. Theinorganic nitrites are not adapted for general use as protectivetreatments applied to steel sheet and. wire as they possess. little orno amnity for the metal and are easily washed or brushed ofl duringhandling and exposure. It was quite unexpected to find that thecompounds covered by this invention were not only water stable but alsostrongly water re-'- copper, pewter, lead, magnesium, cadmium,duralumin," nickel, etc.

We claim:

1. An ammonium metallonitrite having at least one alkyl group of atleast 8 carbon atoms.

2. An ammonium cobaltinitrite having at least one alkyl group of atleast 8 carbon atoms..-

, 3. An ammonium metallonitrite having at least one alkyl group of fromB to 24 carbon atoms.

pellent, and offer excellent protection against eating oils to increasetheir rust protective value,

4. An ammonium metallonitrite having atleast one alkyl group of from 10to 18 carbon atoms.

5. A process which comprises reacting a compound yielding in aqueoussolution a metallonitrite anion with an alkyl amine containing a carbon'chain of at least 8 carbon atoms, in the presence of acetic acid. I 6.Dodecyl ammonium cobaltinitrite. 7. The ammonium cobaltinitrite of themixture of normal primary aliphatic amines having alkyl chains of thesame carbon content and structure and mixed in the same proportion asthe long aliphatic carbon chains of sperm oil.

8. The dipotassium salt of the ammonium lead heptanitrite of the mixtureof normal primary aliphatic amines having alkyl chains of the samecarbon-content and structure and mixed in the same proportion as thelong carbonchains of the acid portion'of coconut oil.

MAX '1'. comm. ISAAC F. warm.

the acid portion of

